SUREFIRE M900AB

[Jackalope33B]

Hey guys, Ive searched this forum, and need help.
I just purchased a Surefire M900AB light. To me, it was not bright enough with the factory bulbs, so I purchased the http://tnvc.com/items/illumination_tools/tnvc_tx4_conversion_head.html
and added it to my light. Im using new Surefire batteries. My question is, when I put the new batteries in the light (it takes 3 of them), the light was bright as he*l for the first 30 minutes. After that, the LED was real dim. I see that TNVC stated a "run time" of 105 minutes for a 9V system. But is this something to expect of only 30 minutes of useable light? Am I missing something here? Will I get more useable light running rechareables?
Any help would be great!

Thanks!

 

[VidPro]

the head would be like running 3X high powered leds with 3 batts.
So a person could figure that it should have a similar runtime to a 1Led light using 1high powered led PER BATTERY (simply). and runtimes for that could possibly reach ~105min (on a good day). on Non rechargable lithium 123 type cell items.
and about ~40-60min Max on rechargable cell items.

if you were using rechargable cell items, then i would not think anything was too far off. if your using good new surfire primary cells , and your sure each of them are new, then it seems off.

First disclaimer warning thing: a dead primary cell, is a dead cell and it is concidered an unsafe cell when it is dead. so dead cells should not be used , and instead disposed of properly.

do you have any ability to test anything?
after it goes dim, test each cell item.
or alternativly test each cell item in a single cell light (if they are still working good).
could it be that one cell item just was not up to par for the job?

also if you could test for the amp draw on the batteries, or put the head itself on a adjustable power supply for testing the amp draw.

Does the light have protection against overheating? because the batteries WILL usually. when hard running small batteries and high bright leds in small packages , heat can be a major issue.
properly protected batteries and even proper driver curcuits can slow down when heat gets too high.
it is inapropriate to "table stand" a high powered light to test for its runtime, a high powered light wants to be cooled by the users hand, and MAY not run at its highest power Non-Stop without a rest. (in fact it is possible to blow the light up doing such things)
A light running high power from its batteries in containtment can certannly overheat, and even thermally overload, a primadonna light that cost buku bucks could have built in thermal protection capability?
does it work again after a rest period?

other notes: at high current draws from a small battery the battery will not have its fullest capacity, temperatures can effect its ability to output capacity , and even rest periods can effect its ability to output its maximim capacity. so batteies actual capacity can be effected by all those things, even some very good ones.

i donno, because i dont have the actual light item, but those are some questions and clues.
i would expect more form the light and the battery than that, and would pre-test another trio of batteries beofre installing, and take another walk with it.
Untill someone with that actual mod comes along . . .

 

[cckw]

Ask the vendor about your run runtime. They aren't the only vendor selling that head, but are pushing it harder then anyone else, so should have the most experience with it. As for rechargeables, they will give you much less run time, not more.

Keep us posted on what you learn from outside this forum. I have been eyeng this head myself.

 

[Jackalope33B]

VID- I do have a meter (not really sure how to use it), but when I did hook up the batteries, they measured 2.95-2.99 each. When I placed all of them into the light, I got a total voltage of 8.92.
During my initial run, the lamp got warm, but not that much above room temp. I did notice that the battery compartment was getting a little hot, but not so hot that I couldnt touch it. When I took the batteries out, they were slightly hot as well. Ive already burned up 6 batteries, and really dont care to use anymore lol.. So rechargables are out then?
I dont know what to do lol..


CCK,

I talked to TNV the other day VIA Email. Here is what I emailed them:

Hey guys, got the LED head the other day. VERY VERY BRIGHT!!!

I do have a question. With every new light that I get, I run it until the batteries die so I know what to expect from it when Im out in the field. The TX4 ran for 25 minutes until the LED began to dim and flicker. Thinking there was something wrong with the batteries, I put in a fresh set of Surefires in it, and got 30 minutes of run time, then the LED went dim once again. I know your chart says a run time of 105 minutes. But what exactly is the run time for the TX4 with the LED staying constantly bright? 30 minutes does not seem all that great for an LED. Im currently using the surefire M900A, its a 3 battery 9V setup.

Any help would be greatly appreciated

And their response:
To understand, you left the light on for a constant 30 minutes? I do know the lights will regulate if the LED is getting too hot and 30 minutes is about right at constant full power on. Not many ever leave a LED on for this long. You can send your whole light assembly in for us to check the system out if you like to insure nothing in your M900 is shorting the Tx4 as well. Thank you!

Vic Di Cosola

Tactical Night Vision Corporation
(909) 796-7000 (Main)
(909) 478-9133 (Fax)
[email protected]
http://www.tnvc.com

So if this is the case of only 30minutes of constant full power on, then this LED Head will be going back! I use a Pelican 7060 LED light for work, and I get about 85 minutes of constant full power before it needs to be recharged. All I can say is Im VERY happy about the brightness with the TX4, but NOT happy at all with 30 minutes of run time. Its kind of hard to swallow that I need to replace batteries in a light that cost more than half as much as I make per hour LOL..
Does anyone know of any other lamps or assembly LED's that I can use on a Surefire M900??

 

[Justin Case]

If the vendor claims significant output at 3V input, then I would have to assume that the MC-E is connected in 4P. Thus, at full power drive current, assuming a driver efficiency of 90%, Vbatt under load of 8V (an optimistic value IMO), Vf 3.3V, and If 2.8A,

0.9 * 8.0V * Ibatt = 3.3V * 2.8A ~9.3W

Thus, Ibatt ~1.3A. This can differ depending on actual driver efficiency, Vbatt, and Vf at the actual drive current. For example, I think a more realistic Vbatt at a load of around 1A is 2.5V per cell, or 7.5V total. But certainly, Vbatt can hit 8V at some point during initial loading before the cells sag down to their quasi steady state value. Therein lies one tricky aspect of estimating run time.

Referencing Silverfox's 123 Shootout data, at a 1A draw, the top 123 primaries seem to have at least 1.4Ah capacity. Thus, estimated run time is 1.4Ah/1.3A ~65 min.

If the vendor claims 105 min when using 3x123A, I think that the only way to do that is to drive the MC-E at less than the 2.8A max drive current. For example, perhaps If is about 2.0A. And maybe they have a batch of low Vf MC-Es. Then,

0.9 * 7.5 * Ibatt = 3.1 * 2 = 6.2

and Ibatt ~0.9A. Now estimated run time is 1.4Ah/0.9A ~90 min, which is in the ballpark.

Seems to me that new SureFire 123As should do better than what you observed. Perhaps the vendor claim of thermal issues is the cause. Probably would have been nice if the vendor caveated their performance claims with a warning about thermal limitations. Just because "not many ever leave a LED on for this long" seems a bit lame for a company purportedly selling gear meant for high speed, low drag applications.

If you have a KT4 TurboHead on your M900, you can use an LED tower module. Search CPF. I've built many of these. CPFer nailbender has a sales thread for some modules. I have some kits that I can also build up into an MC-E tower.

 

[Jackalope33B]

Justin- "If you have a KT4 TurboHead on your M900, you can use an LED tower module. Search CPF. I've built many of these. CPFer nailbender has a sales thread for some modules. I have some kits that I can also build up into an MC-E tower. "

I do have the KT4 Turbo Head. Using a LED Tower Module, what kind of lumens am I to expect, and also what about the runtime at full brightness before the batteries go dead and the LED starts to dim?

Thanks!

 

[Justin Case]

Run time and lumens depend on what LED you put on the tower and what driver you use (i.e., drive current, driver efficiency). You can mount an XP-G R5 and power it at 1000mA drive current or more (up to the datasheet max of 1500mA). You can use an MC-E and drive it at 500mA or more (up to the datasheet max of 700mA) per die. You could go retro and use a Luxeon V or Seoul P4.

If you ran an XP-G R5 at 1000mA, for example, you could get the following:

90% driver efficiency
Vbatt ~7.5V
Vf ~3.2V
If 1000mA

Ibatt = (3.2*1)/(0.9*7.5) ~0.5A

Thus, calculated run time could be about 1.4Ah/0.5A ~3hr.

If you ran a 2S2P MC-E at 500mA per die, then

Ibatt = (2*6.4*0.5)/(0.9*7.5) ~1A and calculated run time could be approx 1.4Ah/1A ~1.4hr.

Emitter lumens can vary from around 200 lumens to possibly over 600 lumens. Out the front lumens will be less due to reflector and glass window losses and bezel shadowing due to the recessed reflector to fit the shock absorption system in the KT4.

 

[cckw]

http://www.tnvc.com

So if this is the case of only 30minutes of constant full power on, then this LED Head will be going back! I use a Pelican 7060 LED light for work, and I get about 85 minutes of constant full power before it needs to be recharged. All I can say is Im VERY happy about the brightness with the TX4, but NOT happy at all with 30 minutes of run time. Its kind of hard to swallow that I need to replace batteries in a light that cost more than half as much as I make per hour LOL..
Does anyone know of any other lamps or assembly LED's that I can use on a Surefire M900??

Couple things #1, it is possible that it just regulated itself as TNV suggested? and #2 No, this was the first viable upgrade option for that light

 

[Jackalope33B]

Justin- All those figures are greek to me.. Im at complete loss when everyone posts things about the voltage, amps, miliamps etc :thinking:..
Im looking for something that is in the ball park of 400-500 lumens. Im looking for more of a flood light rather than a thrower due to the nature of my job. What can you put together that can give me what it is that Im looking for?